It appears that the vent for gasses from our septic system, which I've learned through googling normally comes out of the roof, is instead just a 2 inch pipe extending two feet up from where the waste water exits the house, with nothing on top. I've noticed a septic smell in the basement when someone flushed a toilet, but since yesterday it's suddenly smelling all the time, throughout the house (still seeming to originate at this pipe). Does this mean we need our septic pumped, or is there a possible other explanation? I live in a rural area of the northeast, and our septic system is a tank with gravity feed to a leaching tank. We do have more people living in the house than the system was designed for, but it was pumped in the spring, and our usage has been pretty stable. It's also been very cold - rarely above 10 F and lots of -10 F for a couple weeks, and I don't know if that could have affected something. Any insight would be greatly appreciated.